Propylene-ethylene copolymer compositions suitable for hot fill packaging of foodstuffs

ABSTRACT

Propylene-ethylene copolymer compositions and production methods are provided. The copolymer compositions can be particularly advantageous for use in hot fill packaging of foodstuffs. The propylene-ethylene copolymers can be produced using a Ziegler-Natta catalyst and an alkoxysilane electron donor. The compositions can have propylene as a primary monomer with an ethylene content ranging from 2.0 to 6.0 percent by weight with a xylene soluble content of less than 7.0 percent by weight.

RELATED APPLICATIONS

The present application is based on and claims priority to U.S.Provisional Patent application Ser. No. 62/683,113, filed on Jun. 11,2018, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present disclosure relates to propylene-ethylene copolymercompositions and methods of production. The compositions of the presentdisclosure are particularly well suited for hot fill packaging offoodstuffs.

BACKGROUND

Hot fill packaging is a method that is applied in both the food andbeverage industry and is commonly used for packaging products includingbeverages, dips, and soups. Hot fill packaging is often used as part ofthe pasteurization process for products designed to have extended shelflives lasting up to a year. Hot fill packaging faces various challengesas polymers at high temperatures have a tendency to lose their packagingproperties including stiffness and strength.

As the hot fill packaging interfaces with products meant for humanconsumption, there is a concern that the hot fill packaging may degradein properties. For instance, heating the polymer composition during thehot fill packaging process can cause unwanted breakdown of the polymeror other components in the composition.

In the past, higher melting point polypropylene homopolymers have beenused in hot filled packaging applications in order to preventdistortion. Polypropylene homopolymers, however, have poor transparencyproperties. In order to improve transparency, polypropylene randomcopolymers have been suggested. Polypropylene random copolymers,however, do not possess the heat resistance properties of polypropylenehomopolymers and can also fail to provide long term transparencyproperties.

In view of the above, a need currently exists for a polymer compositionfor producing hot filled packaging that not only has improved stiffnessand heat resistance but also possesses excellent transparencyproperties.

BRIEF SUMMARY

In general, the present disclosure is directed to propylene copolymersthat have been found to have an excellent balance of properties. Thepolymers are particularly well suited to being used in producing hotfill packaging. In particular, the copolymers of the present disclosurehave higher stiffness making them well suited for producing injectionmolded articles. In addition, the polymer composition of the presentdisclosure has extremely low extractables, exhibits low blooming overtime and can be constructed to have a higher heat deflectiontemperature. In addition, the polymer composition can also displayexcellent haze properties. Of particular, advantage, it was discoveredthat the polymer composition of the present disclosure also can maintainhigh haze properties even after thermal aging. In this regard, thepolymer compositions of the present disclosure are well suited toproducing various different types of containers, especially hot fillpackaging containers that may be subjected to multiple heat cycles. Inaccordance with the present disclosure, the containers not only haveexcellent physical properties, but also have long lasting transparencyproperties.

In addition to hot filled packaging containers, the polymer compositionsof the present disclosure can be used to produce various other moldedarticles. For instance, the polymer composition is well suited toproducing storage containers. Such storage containers, for instance, canbe used to store items in non-air conditioned locations, such as attics,garages, warehouses, and other storage facilities. The storagecontainers can include a bottom defining a hollow interior. The bottomcan be made entirely from the polymer composition and can have excellenttransparency properties. The container can also include a lid thatcooperates with the bottom to form a seal.

The present disclosure includes propylene-ethylene copolymercompositions and methods of producing propylene-ethylene copolymercompositions. The compositions can be random copolymers that areparticularly well suited for hot fill packaging of foodstuffs. Thecopolymer compositions can be produced using a Ziegler-Natta catalystand an alkoxysilane electron donor. The compositions can have propyleneas a primary monomer with an ethylene content ranging from 2.0 to 5.0percent by weight. The compositions can have melt flow rates of greaterthan 1 g/10 min, such as greater than 10 g/10 min and a xylene solublecontent of less than 7.0 percent by weight. The compositions, in oneembodiment, have a ratio of xylene solubles weight percent to ethylenecontent weight percent of less than or equal to about 1.5, such as lessthan about 1.4, such as less than about 1.3, such as less than about1.2, such as less than about 1.1, such as even less or equal to 1. Otherfeatures and aspects of the present disclosure are discussed in greaterdetail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof to one skilled in the art, is set forth moreparticularly in the remainder of the specification, which includesreference to the accompanying FIGURES.

FIG. 1 is a graph of xylene solubles weight percent (XS) versus ethylenecontent weight percent (ET) of propylene-ethylene copolymer samplesaccording to the present disclosure.

DETAILED DESCRIPTION

The present disclosure includes propylene-ethylene copolymercompositions and methods of producing propylene-ethylene copolymercompositions. The compositions can include propylene-ethylene randomcopolymers. The propylene-ethylene copolymer compositions can beparticularly well suited for hot fill packaging of foodstuffs.Specifically, the propylene-ethylene copolymer compositions of thepresent disclosure can be used to form rigid hot fill containers andfilms for packaging and sealing food and beverages. The compositions ofthe present disclosure can be particularly beneficial for use withfoodstuffs that must be pasteurized at the time of packaging.

Advantages of the various propylene-ethylene copolymer compositions ofthe present disclosure include increased stiffness for use incontainers. The compositions can also have reduced blooming and reducedhaze, even under elevated temperature conditions and over extendedperiods of time. Compositions of the present disclosure can have reducedextractable and xylene soluble content, making the polymer compositionssafe for consumer use and more readily complaint with U.S. Food and DrugAdministration (FDA) standards. The propylene-ethylene copolymercompositions of the present disclosure can also be used for packagingdesigned for microwave reheating of stored foods.

A first embodiment of the present disclosure includes propylene-ethylenerandom copolymer compositions. The copolymer compositions can beproduced using a Ziegler-Natta catalyst and an alkoxysilane electrondonor. The compositions can have propylene as a primary monomer with anethylene content ranging from 2.0 to 6.0 percent by weight. Thecompositions can have melt flow rates of from 1 to 100 g/10 min and axylene solubles content of less than 7.0 percent by weight.

I. Definitions and Testing Procedures

The term “propylene-ethylene copolymer”, as used herein, is a copolymercontaining a majority weight percent propylene monomer with ethylenemonomer as a secondary constituent. A “propylene-ethylene copolymer”(also sometimes referred to as a polypropylene random copolymer, PPR,PP-R, RCP or RACO) is a polymer having individual repeating units of theethylene monomer present in a random or statistical distribution in thepolymer chain.

Melt flow rate (MFR), as used herein, is measured in accordance with theASTM D 1238 test method at 230° C. with a 2.16 kg weight forpropylene-based polymers. The melt flow rate can be measured in pelletform or on the reactor powder. When measuring the reactor powder, astabilizing package can be added including 2000 ppm of CYANOX 2246antioxidant (methylenebis(4-methyl-6-tert-butylphenol) 2000 ppm ofIRGAFOS 168 antioxidant (tris(2,4-di-tert.-butylphenyl)phosphite) and1000 ppm of acid scavenger ZnO.

Xylene solubles (XS) is defined as the weight percent of resin thatremains in solution after a sample of polypropylene random copolymerresin is dissolved in hot xylene and the solution is allowed to cool to25° C. This is also referred to as the gravimetric XS method accordingto ASTM D5492-98 using a 90 minute precipitation time and is alsoreferred to herein as the “wet method.” Xvlene solubles is measured onthe reactor powder without the addition of any other additives.

The xylene soluble portion is determined by a method adapted from ASTMD5492-06 and also sometimes referred to herein as the “wet method”. Theprocedure consists of weighing 2 g of sample and dissolving the samplein 200 ml o-xylene in a 400 ml flask with 24/40 joint. The flask isconnected to a water cooled condenser and the contents are stirred andheated to reflux under nitrogen (N₂), and then maintained at reflux foran additional 30 minutes. The solution is then cooled in a temperaturecontrolled water bath at 25° C. for 90 minutes to allow thecrystallization of the xylene insoluble fraction. Once the solution iscooled and the insoluble fraction precipitates from the solution, theseparation of the xylene soluble portion (XS) from the xylene insolubleportion (XI) is achieved by filtering through 25 micron filter paper.One hundred ml of the filtrate is collected into a pre-weighed aluminumpan, and the o-xylene is evaporated from this 100 ml of filtrate under anitrogen stream. Once the solvent is evaporated, the pan and contentsare placed in a 100° C. vacuum oven for 30 minutes or until dry. The panis then allowed to cool to room temperature and weighed. The xylenesoluble portion is calculated as XS (wt %)=[(m-m₂)*2/m₁]*100, where m₁is the original weight of the sample used, m₂ is the weight of emptyaluminum pan, and m₃ is the weight of the pan and residue (the asterisk,*, here and elsewhere in the disclosure indicates that the identifiedterms or values are multiplied).

The term “tacticity” generally refers to the relative stereochemistry ofadjacent chiral centers within in a macromolecule or polymer. Forexample, in a propylene-based polymer, the chirality of adjacentmonomers, such as two propylene monomers, can be of either like oropposite configuration. The term “diad” is used to designate twocontiguous monomers and three adjacent monomers are called a “triad” Ifthe chirality of adjacent monomers is of the same relativeconfiguration, the diad is considered isotactic; if opposite inconfiguration, it is termed syndiotactic. Another way to describe theconfigurational relationship is to term contiguous pairs of monomershaving the same chirality as meso (m) and those of oppositeconfiguration racemic (r).

Tacticity or stereochemistry of macromolecules generally andpolypropylene or polypropylene random copolymers in particular can bedescribed or quantified by referring to triad concentration. Anisotactic triad, typically identified with the shorthand reference “mm”,is made up of two adjacent meso diads, which have the sameconfiguration, and so the stereoregularity of the triad is identified as“mm” If two adjacent monomers in a three-monomer sequence have the samechirality and that is different from the relative configuration of thethird unit, this triad has ‘mr’ tacticity. An ‘rr’ triad has the middlemonomer unit having an opposite configuration from either neighbor. Thefraction of each type of triad in the polymer can be determined and whenmultiplied by 100 indicates the percentage of that type found in thepolymer. The mm percentage is used to identify and characterize thepolymers herein.

The sequence distribution of monomers in the polymer may be determinedby ¹³C-NMR, which can also locate ethylene residues in relation to theneighboring propylene residues. ¹³C NMR can be used to measure ethylenecontent, Koenig B-value, triad distribution, and triad tacticity, and isperformed as follows:

The samples are prepared by adding approximately 2.7 g of a 50/50mixture of tetrachloroethane-d2/orthodichlorobenzene containing 0.025 MCr(AcAc)3 to 0.20 g sample in a Norell 1001-7 10 mm NMR tube. Thesamples are dissolved and homogenized by heating the tube and itscontents to 150° C. using a heating block and heat gun. Each sample isvisually inspected to ensure homogeneity.

The data are collected using a Bruker 400 MHz spectrometer equipped witha Bruker Dual DUL high-temperature CryoProbe. The data are acquiredusing 320 transients per data file, a 6 sec pulse repetition delay, 90degree flip angles, and inverse gated decoupling with a sampletemperature of 120° C. All measurements are made on non-spinning samplesin locked mode. Samples are allowed to thermally equilibrate for 7minutes prior to data acquisition. Percent mm tacticity and weight %ethylene are calculated according to methods commonly used in the art,which is briefly summarized as follows.

With respect to measuring the chemical shifts of the resonances, themethyl group of the third unit in a sequence of 5 contiguous propyleneunits consisting of head-to-tail bonds and having the same relativechirality is set to 21.83 ppm. The chemical shift of other carbonresonances are determined by using the above-mentioned value as areference. The spectrum relating to the methyl carbon region (17.0-23ppm) can be classified into the first region (21.1-21.9 ppm), the secondregion (20.4-21.0 ppm), the third region (19.5-20.4 ppm) and the fourthregion (17.0-17.5 ppm). Each peak in the spectrum is assigned withreference to a literature source such as the articles in, for example,Polymer, T. Tsutsui et al., Vol. 30, Issue 7, (1989) 1350-1356 and/orMacromolecules, H. N. Cheng, 17 (1984) 1950-1955, the contents of whichare incorporated herein by reference.

In the first region, the signal of the center methyl group in a PPP (mm)triad is located. In the second region, the signal of the center methylgroup in a PPP (mr) triad and the methyl group of a propylene unit whoseadjacent units are a propylene unit and an ethylene unit resonates(PPE-methyl group). In the third region, the signal of the center methylgroup in a PPP (rr) triad and the methyl group of a propylene unit whoseadjacent units are ethylene units resonate (EPE-methyl group).

PPP (mm), PPP (mr) and PPP (rr) have the following three-propyleneunits-chain structure with head-to-tail bonds, respectively. This isshown in the Fischer projection diagrams below.

The triad tacticity (mm fraction) of the propylene random copolymer canbe determined from a ¹³C-NMR spectrum of the propylene random copolymerusing the following formula:

${{mm}{Fraction}} = \frac{{PPP}({mm})}{{{ppp}({mm})} + {{PPP}({mr})} + {{PPP}({rr})}}$

The peak areas used in the above calculation are not measured directlyfrom the triad regions in the ¹³C-NMR spectrum. The intensities of themr and rr triad regions need to have subtracted from them the areas dueto EPP and EPE sequencing, respectively. The EPP area can be determinedfrom the signal at 30.8 ppm after subtracting from it one-half the areaof the sum of the signals between 26 and 27.2 ppm and the signal at 30.1ppm. The area due to EPE can be determined from the signal at 33.2 ppm.

For convenience, ethylene content is also measured using a FourierTransform Infrared method (FTIR) which is correlated to ethylene valuesdetermined using ¹³C NMR, noted above, as the primary method. Therelationship and agreement between measurements conducted using the twomethods is described in, e.g., J. R. Paxson, J. C. Randall,“Quantitative Measurement of Ethylene Incorporation into PropyleneCopolymers by Carbon-13 Nuclear Magnetic Resonance and InfraredSpectroscopy”, Analytical Chemistry, Vol. 50, No. 13, November 1978,1777-1780.

The “Koenig B-value” or “B-value” or chi statistic is one measure ofrandomness or blockiness in a propylene ethylene random copolymer. AKoenig B-value of 1.0 indicates a random copolymer and a value of zeroindicates complete blocks of monomers A and B; in the presentdisclosure, propylene and ethylene. A Koenig B-value of 2 indicates aperfectly alternating copolymer (i.e., a polymer defined by thestructure A-B-A-B-A-B). The Koenig B-value can be calculated as:B=[EP]/(2[P][E]), where [EP] is the total mole fraction of EP dimers(EP+PE, or (EEP+PPE+PEP+EPE)), and [E] is the mole fraction ethylene,and [P]=1-[E]. See Koenig, Jack L.; Spectroscopy of Polymers, 2nd ed.for details of determining and calculating the Koenig B-value.

Gardner Impact Testing is measured in accordance with ASTM Test No.D5420.

IZOD impact strength is measured in accordance with ASTM Test No D256 onspecimens molded according to ASTM Test D4101.

Flexural Modulus is determined in accordance with ASTM Test D790-10Method A at 1.3 mm/min, using a type 1 specimen per ASTM Test 3641 andmolded according to ASTM Test D4101.

II. Propylene-Ethylene Random Copolymer Compositions

Propylene-ethylene copolymer compositions of the present disclosure caninclude a majority weight percent propylene monomer with ethylenemonomer as a secondary constituent. The ethylene content (ET) of thepropylene-ethylene copolymer compositions of the present disclosure canbe from about 2.0 to up to about 5.0 percent by weight of the copolymer,preferably from about 2.5 to about 5.0 percent by weight, and morepreferably from about 3.0 to about 5.0 percent by weight.

The xylene soluble (XS) fraction for the copolymers of the presentinvention (by the wet method) can be less than or equal to (≤)7.0% byweight of the copolymer, or ≤6.0% by weight, more preferably ≤5.0% byweight, and still more preferably ≤4% by weight, for example, ≤6.5% byweight, ≤5.5% by weight, ≤4.5 by weight, or ≤3.5% by weight. The xylenesoluble (XS) fraction is preferably in the range of from 2.0% to 7.0% byweight, from 2.5% to 6.5% by weight, and more preferably 3.0% to 6.0% byweight. The MFR for the copolymers of the present disclosure can be inthe range of from 10 to 100 g/10 min, more preferably in the range offrom 10 to 50 g/10 min.

The weight ratio of xylene soluble (XS) to the ethylene content (ET) isan important aspect of the embodiments of the present disclosure and canbe referred to as the xylene solubles to ethylene ratio, or the XS/ETratio. The XS/ET ratio of propylene-ethylene copolymer compositions ofthe present disclosure can be less than or equal to (≤)1.5, or ≤1.4,more preferably ≤1.2, and still more preferably ≤1.0, for example, ≤1.8,≤1.4, ≤1.1, or ≤0.95. The XS/ET ratio can also be in the range of from0.5 to 1.51, from 1.0 to 1.5, from 1.1 to 1.4, and more preferably from1.15 to 1.35.

The xylene soluble wt. % (XS) and the ethylene wt. % (ET) of thecopolymer compositions of the present disclosure can be described bytheir position on a scatter plot of xylene soluble wt. % (XS) versusethylene wt. % (ET), as shown in FIG. 1 . For example, the xylenesoluble wt. % (XS) and the ethylene wt. % (ET) of embodiments of thepresent disclosure can fall below a line defined by the equationXS=2.0e^(0.297(ET)), such as below the line XS=1.9e^(0.297(ET)), andsuch as below the line XS=1.8e^(0.297(ET)). The xylene soluble wt. %(XS) and the ethylene wt. % (ET) of embodiments of the presentdisclosure can also be above a line defined by the equationXS=1.1e^(0.297(ET)), such as above the line XS=1.3e^(0.297(ET)), such asabove the line XS=1.4e^(0.297(ET)), such as above the lineXS=1.5e^(0.297(ET)), and such as above the line XS=1.6e^(0.297(ET)).

In one embodiment, the polymer composition may contain a nucleator. Forinstance, the nucleator may be an alpha nucleator. Examples ofnucleators and/or clarifiers that may be used in the polymer compositioninclude benzene amid derivatives, sorbitol derivatives, nonitolderivatives, and mixtures thereof. Particular examples of nucleatingagents include NA-11 nucleator marketed by Adeka Palmarole SAS, such assodium 2,2′-methylene-bis-(4,6-di-tert-butylphenyl)phosphate. Othernucleators that may be used include the HPN nucleators marketed byMilliken and Company of Spartanburg, South Carolina including HPN-600ei.Other suitable clarifiers from Milliken include Millad NX8000 and Millad3988i.

The copolymer of the present disclosure generally has a relatively broadmolecular weight distribution. For instance, the molecular weightdistribution (Mw/Mn) is generally greater than about 3.5, such asgreater than about 3.8, such as greater than about 4, such as greaterthan about 4.3, such as greater than about 4.5, such as greater thanabout 4.8, such as greater than about 5, such as greater than about 5.2,such as greater than about 5.5, such as greater than about 5.7, such asgreater than about 6 and is generally less than about 10, such as lessthan about 8, such as less than about 7.5. The weight average molecularweight is determined by GPC.

III. Propylene-Ethylene Random Copolymer Production

Embodiments of the present invention can be made by any process forpolymerizing propylene-based polymers known in the art. This includesthe UNIPOL® gas phase process, using a supported Ziegler-Natta catalyst.Particularly preferable are CONSISTA® catalysts available from W.R.Grace & Co., Columbia, Maryland. Suitable polypropylene randomcopolymers may be produced using a single reactor or multiple reactorsto produce a multimodal product. For some embodiments, it is preferredto use internal electron donors which do not contain phthalates.

Processes and catalyst compositions for preparing useful PP-R copolymersare disclosed, for example, in WO 2011/084628, and others are generallydisclosed in U.S. Pat. Nos. 7,381,779; 7,491,670; 7,678,868; 7,781,363;and 7,989,383. Propylene-ethylene random copolymers having highmolecular weight and low MFR are produced using stereospecific catalystsand sometimes referred to as “6th generation” Ziegler-Natta catalystscontaining non-phthalate internal donors, such as those disclosed inU.S. Pat. Nos. 8,288,585; 8,536,372; 8,778,826; US 2013/0338321; and/orWO 2010/078494 and others. Also suitable are so-called “4th generation”Ziegler-Natta catalysts, typically containing phthalate internal donors(e.g., diisobutyl phthalate, DIBP). Each of the forgoing cited patentsare hereby incorporated by reference.

Procatalyst compositions suitable for use in producing the polypropylenerandom (PP-R) copolymers include Ziegler-Natta procatalyst compositions.Any conventional Ziegler-Natta procatalyst may be used in the presentcatalyst composition as is commonly known in the art provided it iscapable of producing the claimed PP-R copolymers. In an embodiment, theZiegler-Natta procatalyst composition contains titanium moiety such astitanium chloride, magnesium moiety such as magnesium chloride, and aninternal electron donor.

In an embodiment, the internal electron donor comprises a substitutedphenylene aromatic diester. In an embodiment, a 1,2-phenylene aromaticdiester is provided. The substituted 1,2-phenylene aromatic diester hasthe structure (I) below

wherein R₁-R₁₄ are the same or different Each of R₁-R₁₄ is selected froma hydrogen, substituted hydrocarbyl group having 1 to 20 carbon atoms,an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, analkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinationsthereof. At least one of R₁-R₁₄ is not hydrogen.

As used herein, the term “hydrocarbyl” and “hydrocarbon” refer tosubstituents containing only hydrogen and carbon atoms, includingbranched or unbranched, saturated or unsaturated, cyclic, polycyclic,fused, or acyclic species, and combinations thereof. Nonlimitingexamples of hydrocarbyl groups include alkyl-, cycloalkyl-, alkenyl-,alkadienyl-, cycloalkenyl-, cycloalkadienyl-, aryl-, aralkyl, alkylaryl,and alkynyl-groups.

As used herein, the terms “substituted hydrocarbyl” and “substitutedhydrocarbon” refer to a hydrocarbyl group that is substituted with oneor more nonhydrocarbyl substituent groups. A nonlimiting example of anonhydrocarbyl substituent group is a heteroatom. As used herein, a“heteroatom” refers to an atom other than carbon or hydrogen. Theheteroatom can be a non-carbon atom from Groups IV, V, VI, and VII ofthe Periodic Table Nonlimiting examples of heteroatoms include: halogens(F, Cl, Br, I), N, O, P, B, S, and Si. A substituted hydrocarbyl groupalso includes a halohydrocarbyl group and a silicon-containinghydrocarbyl group. As used herein, the term “halohydrocarbyl” grouprefers to a hydrocarbyl group that is substituted with one or morehalogen atoms. As used herein, the term “silicon-containing hydrocarbylgroup” is a hydrocarbyl group that is substituted with one or moresilicon atoms. The silicon atom(s) may or may not be in the carbonchain.

The procatalyst precursor can include (i) magnesium, (ii) a transitionmetal compound of an element from Periodic Table groups IV to VIII,(iii) a halide, an oxyhalide, and/or an alkoxide of (i) and/or (ii), and(iv) combinations of (i), (ii), and (iii). Nonlimiting examples ofsuitable procatalyst precursors include halides, oxyhalides, andalkoxides of magnesium, manganese, titanium, vanadium, chromium,molybdenum, zirconium, hafnium, and combinations thereof.

In an embodiment, the procatalyst precursor is a magnesium moietycompound (MagMlo), a mixed magnesium titanium compound (MagTi), or abenzoate-containing magnesium chloride compound (BenMag) in anembodiment, the procatalyst precursor is a magnesium moiety (“MagMo”)precursor. The “MagMo precursor” contains magnesium as the sole metalcomponent. The MagMo precursor includes a magnesium moiety. Nonlimitingexamples of suitable magnesium moieties include anhydrous magnesiumchloride and/or its alcohol adduct, magnesium alkoxide or aryloxide,mixed magnesium alkoxy halide, and/or carboxylated magnesium dialkoxideor aryloxide. In one embodiment, the MagMo precursor is a magnesiumdi(C₁₋₄)alkoxide. In a further embodiment, the MagMo precursor isdiethoxymagnesium.

In an embodiment, the procatalyst precursor is a mixedmagnesium/titanium compound (“MagTi”). The “MagTi precursor” has theformula Mg_(d)Ti(OR^(c))_(f)X_(g) wherein R^(c) is an aliphatic oraromatic hydrocarbon radical having 1 to 14 carbon atoms or COR′ whereinR′ is an aliphatic or aromatic hydrocarbon radical having 1 to 14 carbonatoms, each OR^(c) group is the same or different; X is independentlychlorine, bromine or iodine, preferably chlorine; d is 0.5 to 56, or 2to 4; f is 2 to 116 or 5 to 15; and g is 0.5 to 116, or 1 to 3. Theprecursors are prepared by controlled precipitation through removal ofan alcohol from the reaction mixture used in their preparation. In anembodiment, a reaction medium comprises a mixture of an aromatic liquid,especially a chlorinated aromatic compound, most especiallychlorobenzene, with an alkanol, especially ethanol. Suitablehalogenating agents include titanium tetrabromide, titaniumtetrachloride or titanium trichloride, especially titaniumtetrachloride. Removal of the alkanol from the solution used in thehalogenation results in precipitation of the solid precursor, havingespecially desirable morphology and surface area. Moreover, theresulting precursors are particularly uniform in particle size.

The present procatalyst composition can also include an internalelectron donor. As used herein, an “internal electron donor” is acompound added during formation of the procatalyst composition thatdonates a pair of electrons to one or more metals present in theresultant procatalyst composition. Not bounded by any particular theory,it is believed that the internal electron donor assists in regulatingthe formation of active sites and thus enhances catalyststereoselectivity. In an embodiment, the internal electron donorincludes a substituted phenylene aromatic diester of structure (1),identified above.

In an embodiment, a procatalyst composition is provided which includes acombination of a magnesium moiety, a titanium moiety and an internalelectron donor. The internal electron donor includes the substitutedphenylene aromatic diester. The procatalyst composition is produced byway of a halogenation procedure described in detail in U.S. Pat. No.8,536,372, incorporated herein by reference, which converts theprocatalyst precursor and the substituted phenylene aromatic diesterdonor into the combination of the magnesium and titanium moieties, intowhich the internal electron donor is incorporated. The procatalystprecursor from which the procatalyst composition is formed can be themagnesium moiety precursor, the mixed magnesium/titanium precursor, orthe benzoate-containing magnesium chloride precursor.

In an embodiment, the magnesium moiety is a magnesium halide. In anotherembodiment, the magnesium halide is magnesium chloride, or magnesiumchloride alcohol adduct. In an embodiment, the titanium moiety is atitanium halide such as a titanium chloride. In another embodiment thetitanium moiety is titanium tetrachloride. In another embodiment, theprocatalyst composition includes a magnesium chloride support upon whicha titanium chloride is deposited and upon which the internal electrondonor is incorporated.

In an embodiment, the internal electron donor of the procatalystcomposition includes the substituted phenylene aromatic diester ofstructure (I), illustrated above, wherein R₁-R₁₄ are the same ordifferent; each of R₁-R₁₄ is selected from hydrogen, a substitutedhydrocarbyl group having 1 to 20 carbon atoms, an unsubstitutedhydrocarbyl group having 1 to 20 carbon atoms, an alkoxy group having 1to 20 carbon atoms, a heteroatom, and combinations thereof, and at leastone of R₁-R₁₄ is not hydrogen.

In an embodiment, at least one (or two, or three, or four) R group(s) ofR₁-R₄, is selected from a substituted hydrocarbyl group having 1 to 20carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbonatoms, an alkoxy group having 1 to 20 carbon atoms, a heteroatom, andcombinations thereof.

In an embodiment, at least one (or some, or all) R group(s) of R₅-R₁₄ isselected from a substituted hydrocarbyl group having 1 to 20 carbonatoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms,an alkoxy group having 1 to 20 carbon atoms, a heteroatom, andcombinations thereof. In another embodiment, at least one of R₅-R₉ andat least one of R₁₀-R₁₄ is selected from a substituted hydrocarbyl grouphaving 1 to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, aheteroatom, and combinations thereof.

In an embodiment, at least one of R₁-R₄ and at least one of R₅-R₁₄ isselected from a substituted hydrocarbyl group having 1 to 20 carbonatoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms,an alkoxy group having 1 to 20 carbon atoms, a heteroatom, andcombinations thereof. In another embodiment, at least one of R₁-R₄ atleast one R₅-R₉ of and at least one of R₁₀-R₁₄ is selected from asubstituted hydrocarbyl group having 1 to 20 carbon atoms, anunsubstituted hydrocarbyl group having 1 to 20 carbon atoms, an alkoxygroup having 1 to 20 carbon atoms, a heteroatom, and combinationsthereof.

In an embodiment, any consecutive R groups in R₁-R₄, and/or anyconsecutive R groups in R₅-R₉, and/or any consecutive R groups inR₁₀-R₁₄ may be linked to form an inter-cyclic or an intra-cyclicstructure. The inter-/intra-cyclic structure may or may not be aromatic.In an embodiment, the inter-/intra-cyclic structure is a C₅ or a C₆membered ring.

In an embodiment, at least one of R₁-R₄, is selected from a substitutedhydrocarbyl group having 1 to 20 carbon atoms, an unsubstitutedhydrocarbyl group having 1 to 20 carbon atoms, and combinations thereof.Optionally, at least one of R₅-R₁₄ may be a halogen atom or an alkoxygroup having 1 to 20 carbon atoms. Optionally, R₁-R₄, and/or R₅-R₉,and/or R₁₀-R₁₄ may be linked to form an inter-cyclic structure or anintra-cyclic structure. The inter-cyclic structure and/or theintra-cyclic structure may or may not be aromatic.

In an embodiment, any consecutive R groups in R₁-R₄, and/or in R₅-R₉,and/or in R₁₀-R₁₄, may be members of a C₅-C₆-membered ring.

In an embodiment, structure (I) includes R₁, R₃ and R₄ as hydrogen. R₂is selected from a substituted hydrocarbyl group having 1 to 20 carbonatoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms,and combinations thereof. R₅-R₁₄ are the same or different and each ofR₅-R₁₄ is selected from hydrogen, a substituted hydrocarbyl group having1 to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a halogen,and combinations thereof.

In an embodiment, R₂ is selected from a C₁-C₈ alkyl group, a C₃-C₆cycloalkyl, or a substituted C₃-C₆ cycloalkyl group R₂ can be a methylgroup, an ethyl group, a n-propyl group, an isopropyl group, a t-butylgroup, an isobutyl group, a sec-butyl group, a2,4,4-trimethylpentan-2-yl group, a cyclopentyl group, and a cyclohexylgroup.

In an embodiment, structure (I) includes R₂ that is methyl, and each ofR₅-R₁₄ is hydrogen. In an embodiment, structure (I) includes R₂ that isethyl, and each of R₅-R₁₄ is hydrogen. In an embodiment, structure (I)includes R₂ that is t-butyl, and each of R₅-R₁₄ is hydrogen. In anembodiment, structure (I) includes R₂ that is ethoxycarbonyl, and eachof R₅-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₂, R₃ and R₄ each as hydrogenand R₁ is selected from a substituted hydrocarbyl group having 1 to 20carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbonatoms, and combinations thereof. R₅-R₁₄ are the same or different andeach is selected from hydrogen, a substituted hydrocarbyl group having 1to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a halogen,and combinations thereof.

In an embodiment, structure (I) includes R₁ that is methyl, and each ofR₅-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₂ and R₄ that are hydrogen andR₁ and R₃ are the same or different. Each of R₁ and R₃ is selected froma substituted hydrocarbyl group having 1 to 20 carbon atoms, anunsubstituted hydrocarbyl group having 1 to 20 carbon atoms, andcombinations thereof. R₅-R₁₄, are the same or different and each ofR₅-R₁₄ is selected from a substituted hydrocarbyl group having 1 to 20carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbonatoms, an alkoxy group having 1 to 20 carbon atoms, a halogen, andcombinations thereof.

In an embodiment, structure (I) includes R₁ and R₃ that are the same ordifferent. Each of R₁ and R₃ is selected from a C₁-C₈ alkyl group, aC₃-C₆ cycloalkyl group, or a substituted C₃-C₈ cycloalkyl group. R₅-R₁₄,are the same or different and each of R₅-R₁₄ is selected from hydrogen,a C₁-C₈ alkyl group, and a halogen. Nonlimiting examples of suitableC₁-C₈ alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl,i-butyl, t-butyl, n-pentyl, i-pentyl, neopentyl, t-pentyl, n-hexyl, and2,4,4-trimethylpentan-2-yl group Nonlimiting examples of suitable C₃-C₆cycloalkyl groups include cyclopentyl and cyclohexyl groups. In afurther embodiment, at least one of R₅-R₁₄ is a C₁-C₈ alkyl group or ahalogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR; that is a t-butyl group. Each of R₂, R₄ and R₅-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ and R₃ that is an isopropylgroup. Each of R₂, R₄ and R₅-R₁₄ is hydrogen.

In an embodiment, structure (I) includes each of R₁, R₅, and R₁₀ as amethyl group and R₃ is a t-butyl group. Each of R₂, R₄, R₆-R₉ andR₁₁-R₁₄ is hydrogen.

In an embodiment, structure (I) includes each of R₁, R₇, and R₁₂ as amethyl group and R₃ is a t-butyl group. Each of R₂, R₄, R₅, R₆, Ra, R₉,R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ as a methyl group and R₃ isa t-butyl group. Each of R₇ and R₁₂ is an ethyl group. Each of R₂, R₄,R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes each of R₁, R₅, R₇, R₉, R₁₀,R₁₂, and R₁₄ as a methyl group and R₃ is a t-butyl group. Each of R₂,R₄, R₆, R₈, R₁₁, and R₁₃ is hydrogen.

In an embodiment, structure (I) includes R₁ as a methyl group and R₃ isa t-butyl group. Each of R₅, R₇, R₉, R₁₀, R₁₂, and R₁₄ is an i-propylgroup. Each of R₂, R₄, R₆, R₈, R₁₁, and R₁₃ is hydrogen.

In an embodiment, the substituted phenylene aromatic diester has astructure selected from the group consisting of structures (II)-(V),including alternatives for each of R₁ to R₁₄, that are described indetail in U.S. Pat. No. 8,536,372, which is incorporated herein byreference.

In an embodiment, structure (O) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is an ethoxy group. Each ofR₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇, and R₁₂ is a fluorine atom. Each ofR₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇, and R₁₂ is a chlorine atom. Each ofR₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (O) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is a bromine atom. Each of R₂,R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (1) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is an iodine atom. Each of R₂,R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₆, R₇, R₁₁, and R₁₂ is a chlorine atom.Each of R₂, R₄, R₅, R₈, R₉, R₁₀, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR; is a t-butyl group. Each of R₆, R₁, R₁₁, and R₁₃ is a chlorine atom.Each of R₂, R₄, R₅, R₇, R₉, R₁₀, R₁₂, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₂, R₄ and R₅-R₁₄ is a fluorine atom.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is a trifluoromethyl group.Each of R₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is an ethoxycarbonyl group.Each of R₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, R₁ is methyl group and R₃ is a t-butyl group. Each ofR₇ and R₁₂ is an ethoxy group. Each of R₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁,R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a t-butyl group. Each of R₇ and R₁₂ is a diethylamino group. Eachof R₂, R₄, R₅, R₆, R₈, R₉, R₁₀, R₁₁, R₁₃, and R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group andR₃ is a 2,4,4-trimethylpentan-2-yl group. Each of R₂, R₄ and R₅-R₁₄ ishydrogen.

In an embodiment, structure (I) includes R₁ and R₃, each of which is asec-butyl group. Each of R₂, R₄, and R₅-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ and R₄ that are each amethyl group. Each of R₂, R₃, R₅-R₉, and R₁₀-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁ that is a methyl group. R₄is an i-propyl group. Each of R₂, R₃, R₅-R₉ and R₁₀-R₁₄ is hydrogen.

In an embodiment, structure (I) includes R₁, R₃, and R₄, each of whichis an i-propyl group. Each of R₂, R₅-R₉ and R₁₀-R₁₄ is hydrogen.

In an embodiment, another procatalyst composition is provided. Theprocatalyst composition includes a combination of a magnesium moiety, atitanium moiety and a mixed internal electron donor. As used herein, a“mixed internal electron donor” is (i) a substituted phenylene aromaticdiester, (ii) an electron donor component that donates a pair ofelectrons to one or more metals present in the resultant procatalystcomposition, and (iii) optionally other components. In an embodiment,the electron donor component is a phthalate, a diether, a benzoate, andcombinations thereof. The procatalyst composition with the mixedinternal electron donor can be produced by way of the procatalystproduction procedure as disclosed in the previously granted patents andpublications identified herein.

For example, suitable catalyst compositions comprise a pro-catalystcomposition, a co-catalyst, and an external electron donor or a mixedexternal electron donor (M-EED) of two or more different components.Suitable external donors include one or more activity limiting agents(ALA), one or more selectivity control agents (SCA) or both an ALA andan SCA. As used herein, an “external electron donor” is a component or acomposition comprising a mixture of components added independent ofprocatalyst formation that modifies the catalyst performance. As usedherein, an “activity limiting agent” is a composition that decreasescatalyst activity as the polymerization temperature in the presence ofthe catalyst rises above a threshold temperature (e.g., temperaturegreater than about 85° C.). A “selectivity control agent” is acomposition that improves polymer tacticity, wherein improved tacticityis generally understood to mean increased tacticity or reduced xylenesolubles or both. It should be understood that the above definitions arenot mutually exclusive and that a single compound may be classified, forexample, as both an activity limiting agent and a selectivity controlagent.

In an embodiment, the external electron donor includes an alkoxysilane.The alkoxysilane has the general formula:SiR_(m)(OR′)_(4-m)  (I)

-   -   where R independently each occurrence is hydrogen or a        hydrocarbyl or an amino group optionally substituted with one or        more substituents containing one or more Group 14, 15, 16, or 17        heteroatoms, said R containing up to 20 atoms not counting        hydrogen and halogen; R′ is a C₁₋₄ alkyl group; and m is 0, 1, 2        or 3. In an embodiment, R is C₆₋₁₂ arylalkyl or aralkyl, C₃₋₁₂        cycloalkyl, C₃₋₁₂ branched alkyl, or C₃₋₁₂ cyclic or acyclic        amino group, R′ is C₁₋₄ alkyl, and m is 1 or 2.

Nonlimiting examples of suitable silane compositions includedicvclopentyldimethoxysilane; di-tert-butyldimethoxysilane;methylcyclohexyldimethoxysilane; methylcyclohexyldiethoxysilane;ethylcyclohexyldimethoxysilane; diphenyldimethoxysilane;diisopropyldimethoxysilane; di-n-propyldimethoxysilane;diisobutyldimethoxysilane; diisobutyldiethoxysilane;isobutylisopropyldimethoxysilane; di-n-butvldimethoxysilane;cyclopentyltrimethoxysilane; isopropyltrimethoxysilane,n-propyltrimethoxysilane, n-propyltriethoxysilane, ethyltriethoxysilane;tetramethoxysilane; tetraethoxysilane; diethylaminotriethoxysilane;cyclopentylpyrrolidinodimethoxysilane; bis(pyrrolidino)dimethoxysilane;bis(perhydroisoquinolino)dimethoxysilane; and dimethyldimethoxysilane.In an embodiment, the silane composition is dicyclopentyldimethoxysilane(DCPDMS); methylcyclohexyldimethoxysilane (MChDMS); orn-propyltrimethoxysilane (NPTMS); and any combination of thereof.

In an embodiment, the selectivity control agent component can be amixture of 2 or more alkoxysilanes. In a further embodiment, the mixturecan be dicyclopentyldimethoxysilane and methylcyclohexyldimethoxysilane,dicyclopentyldimethoxysilane and tetraethoxysilane, ordicyclopentyldimethoxysilane and n-propyltriethoxysilane. In anembodiment, the mixed external electron donor may include a benzoate, asuccinate, and/or a diol ester. In an embodiment, the mixed externalelectron donor includes 2,2,6,6-tetramethylpiperidine as an SCA. Inanother embodiment, the mixed external electron donor includes a dietheras both an SCA and an ALA.

A mixed external electron donor system can also include an activitylimiting agent (ALA). An ALA inhibits or otherwise preventspolymerization reactor upset and ensures continuity of thepolymerization process. Typically, the activity of Ziegler-Nattacatalysts increases as the reactor temperature rises. Ziegler-Nattacatalysts also typically maintain high activity near the melting pointtemperature of the polymer produced. The heat generated by theexothermic polymerization reaction may cause polymer particles to formagglomerates and may ultimately lead to disruption of continuity for thepolymer production process. The ALA reduces catalyst activity atelevated temperature, thereby preventing reactor upset, reducing (orpreventing) particle agglomeration, and ensuring continuity of thepolymerization process.

The activity limiting agent may be a carboxylic acid ester, a diether, apoly(alkene glycol), a diol ester, and combinations thereof. Thecarboxylic acid ester can be an aliphatic or aromatic, mono- orpoly-carboxylic acid ester. Nonlimiting examples of suitablemonocarboxylic acid esters include ethyl and methyl benzoate; ethylp-methoxybenzoate; methyl p-ethoxybenzoate; ethyl p-ethoxybenzoate,ethyl p-isopropoxybenzoate; ethyl acrylate; methyl methacrylate; ethylacetate; ethyl p-chlorobenzoate; hexyl p-aminobenzoate, isopropylnaphthenate; n-amyl toluate; ethyl cyclohexanoate and propyl pivalate.

Nonlimiting examples of suitable polycarboxylic acid esters includedimethyl phthalate; diethyl phthalate; di-n-propyl phthalate;diisopropyl phthalate, di-n-butyl phthalate; diisobutvl phthalate;di-tert-butyl phthalate; diisoamyl phthalate; di-tert-amyl phthalate;dineopentyl phthalate; di-2-ethylhexyl phthalate; di-2-ethyldecvlphthalate; diethyl terephthalate; dioctyl terephthalate; andbis[4-(vinyloxy)butyl]terephthalate.

The aliphatic carboxylic acid ester may be a C₄-C₃₀ aliphatic acidester, may be a mono- or a poly- (two or more) ester, may be straightchain or branched, may be saturated or unsaturated, and any combinationthereof. The C₆-C₃₀ aliphatic acid ester may also be substituted withone or more Group 14, 15 or 16 heteroatom containing substituents.Nonlimiting examples of suitable C₆-C₃₀ aliphatic acid esters includeC₁₋₂₀ alkyl esters of aliphatic C₆₋₃₀ monocarboxylic acids. C₁₋₂₀ alkylesters of aliphatic C₈₋₂₀ monocarboxylic acids, C₁₋₄ allyl mono- anddiesters of aliphatic C₈₋₂₀ monocarboxylic acids and dicarboxylic acids,C₁₋₄ alkyl esters of aliphatic C₈₋₂₀ monocarboxylic acids anddicarboxylic acids, and C₆₋₂₀ mono- or polycarboxylate derivatives ofC₂₋₁₀₀ (poly) glycols or C₂₋₁₀₀ (poly)glycol ethers. In a furtherembodiment, the C₆-C₃₀ aliphatic acid ester may be a laurate, amyristate, a palmitate, a stearate, an oleate, a sebacate,(poly)(alkylene glycol) mono- or diacetates, (poly)(alkylene glycol)mono- or di-myristates, (poly)(alkylene glycol) mono- or di-laurates,(poly)(alkylene glycol) mono- or di-oleates, glyceryl tri(acetate),glyceryl tri-ester of C₂₋₄₀ aliphatic carboxylic acids, and mixturesthereof. In a further embodiment, the C₆-C₂₀ aliphatic ester isisopropyl myristate or di-n-butyl sebacate.

In an embodiment, the activity limiting agent includes a diether. Thediether can be a 1,3-diether compound represented by the followingstructure (VI):

wherein R₁ to R₄ are independently of one another an alkyl, aryl oraralkyl group having up to 20 carbon atoms, which may optionally containa group 14, 15, 16, or 17 heteroatom, and R₁ and R₂ may be a hydrogenatom. The dialkylether may linear or branched, and may include one ormore of the following groups: alkyl, cycloaliphatic, aryl, alkylaryl orarylalkyl radicals with 1-18 carbon atoms, and hydrogen. R₁ and R₂ maybe linked to form a cyclic structure, such as cyclopentadiene orfluorene.

In an embodiment, the activity limiting agent includes a succinatecomposition having the following structure (VII):

wherein R and R′ may be the same or different, R and/or R′ including oneor more of the following groups hydrogen, linear or branched alkyl,alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionallycontaining heteroatoms. One or more ring structures can be formed viaone or both 2- and 3-position carbon atom.

In an embodiment, the activity limiting agent includes a diol ester asrepresented by the following structure (VIII):

wherein n is an integer from 1 to 5. R₁ and R₂, may be the same ordifferent, and each may be selected from hydrogen, methyl, ethyl,n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, allyl, phenyl, orhalophenyl group. R₃, R₄, R₅, R₆, R₇, and R₈ may be the same ordifferent, and each may be selected from hydrogen, halogen, substituted,or unsubstituted hydrocarbyl having 1 to 20 carbon atoms. R₁-R₆, groupsmay optionally contain one or more heteroatoms replacing carbon,hydrogen or both, the hetero-atom selected from nitrogen, oxygen,sulfur, silicon, phosphorus and a halogen. R₇ and R₈, may be the same ordifferent, and may be bonded to any carbon atom of the 2-, 3-, 4-, 5-,and 6-position of either phenyl ring.

Individual external electron donor components can be added into thereactor separately or two or more can be mixed together in advance andthen added into the reactor as a mixture. In the mixture, more than oneselectivity control agent or more than one activity limiting agent canbe used. In an embodiment, the mixture is dicyclopentyldimethoxysilaneand isopropyl myristate; diisopropyldimethoxysilane and isopropylmyristate; dicyclopentyldimethoxysilane and poly(ethylene glycol)laurate; dicyclopentyldimethoxysilane and isopropyl myristate andpoly(ethylene glycol) dioleate; methylcyclohexyldimethoxysilane andisopropyl myristate; n-propyltrimethoxysilane and isopropyl myristate;dimethyldimethoxysilane and methylcyclohexyldimethoxysilane andisopropyl myristate; dicyclopentyldimethoxysilane andn-propyltriethoxysilane and isopropyl myristate;diisopropyldimethoxysilane and n-propyltriethoxysilane and isopropylmyristate; and dicyclopentyldimethoxysilane and tetraethoxysilane andisopropyl myristate; dicyclopentyldimethoxysilane anddiisopropyldimethoxysilane and n-propyltriethoxysilane and isopropylmyristate; and combinations thereof.

The catalyst composition includes a cocatalyst. The cocatalyst for usewith the Ziegler-Natta procatalyst composition may be an aluminumcontaining composition. Nonlimiting examples of suitable aluminumcontaining compositions include organoaluminum compounds, such astrialkylaluminum; dialkylaluminum hydride; alkylaluminum dihydride;dialkylaluminum halide; alkylaluminumdihalide; dialkylaluminum alkoxide,and alkylaluminum dialkoxide-compounds containing from 1-10, or 1-6carbon atoms in each alkyl- or alkoxide-group. In an embodiment, thecocatalyst is a C₁₋₄ trialkylaluminum compound, such as triethylaluminum(TEA). The catalyst composition includes a mole ratio of aluminum (Al)to (SCA(s)+ALA(s)) of 0.5-25:1; or 1.0-20:1; or 1.5-15:1; or less thanabout 6.0, or less than about 5, or less than 4.5. In an embodiment, theAl:(SCA(s)+ALA(s)) mole ratio is 0.5-4.0:1. The total-SCA to ALA moleratio is 0.01-20:1; 0.10-5.00:1; 0.43-2.33:1, or 0.54-1.85:1; or0.67-1.5:1.

IV. Hot Fill Packaging

In another embodiment, a hot fill packaging can be produced using thepropylene-ethylene copolymers discussed above. The hot fill packagingcan be injection molded. Preferably, the resin used in the hot fillpackaging comprises 100% of the propylene ethylene copolymer resins ofthe present invention, but up to 5%, 10%, 15% or even 25% by weight ofone or more additional resins other than the copolymers defined hereinmay be added.

The copolymer composition used for making the hot fill packagingpreferably contains antioxidants and acid scavengers, and in someapplications may preferably also contain other additives commonly usedin PP such as nucleators, clarifiers, mold release agents, antistats,slip agents, UV stabilizers, and colorants (pigments).

In one embodiment, the copolymer composition can further contain a typeof nucleator called a clarifying agent or clarifier. The clarifyingagent can be added to further improve the transparency properties of thecomposition. The clarifying agent, for instance, can comprise a compoundcapable of producing a gelation network within the composition.

In one embodiment, the clarifying agent may comprise a sorbitolcompound, such as a sorbitol acetal derivative. In one embodiment, forinstance, the clarifying agent may comprise a dibenzyl sorbitol.

With regard to sorbitol acetal derivatives that can be used as anadditive in some embodiments, the sorbitol acetal derivative is shown inFormula (1):

wherein R1-R5 comprise the same or different moieties chosen fromhydrogen and a C1-C3 alkyl.

In some embodiments, R1-R5 are hydrogen, such that the sorbitol acetalderivative is 2,4-dibenzylidene sorbitol (“DBS”). In some embodiments,R1, R4, and R5 are hydrogen, and R2 and R3 are methyl groups, such thatthe sorbitol acetal derivative is1,3:2,4-di-p-methyldibenylidene-D-sorbitol (“MDBS”). In someembodiments, R1-R4 are methyl groups and R5 is hydrogen, such that thesorbitol acetal derivative is 1,3:2,4-Bis (3,4-dimethylobenzylideno)sorbitol (“DMDBS”). In some embodiments, R2, R3, and R5 are propylgroups (—CH2-CH2-CH3), and R1 and R4 are hydrogen, such that thesorbitol acetal derivative is1,2,3-trideoxy-4,6:5,7-bis-O-(4-propylphenyl methylene) nonitol(“TBPMN”).

Other embodiments of clarifying agents that may be used include:

-   1,3:2,4-dibenzylidenesorbitol-   1,3:2,4-bis(p-methylbenzylidene)sorbitol-   Di(p-methylbenzylidene)Sorbitol-   Di(p-ethylbenzylidene)Sorbitol-   Bis(5′,6′,7′,8′-tetrahvdro-2-naphtylidene)Sorbitol

In one embodiment, the clarifying agent may also comprise a bisamide.The clarifying agents described above can be used alone or incombination.

When present in the polymer composition, one or more clarifying agentsare generally added in an amount greater than about 1,500 ppm, such asin an amount greater than about 1,800 ppm, such as in an amount greaterthan about 2,000 ppm, such as in an amount greater than about 2,200 ppm.One or more clarifying agents are generally present in an amount lessthan about 20,000 ppm, such as less than about 15,000 ppm, such as lessthan about 10,000 ppm, such as less than about 8,000 ppm, such as lessthan about 5,000 ppm.

V. EXAMPLES Example No. 1

Propylene-ethylene random copolymer samples were produced and theirproperties tested in accordance with the procedures outlined above. Theproperties and experimental results are outlined in Table 1. Also, FIG.1 includes a graph of xylene solubles to ethylene content.

The propylene-ethylene random copolymers were produced with astereospecific 6^(th) generation Ziegler-Natta magnesiumsupported/titanium-based catalyst. The catalyst contained anon-phthalate internal donor producing polymers having a broadermolecular weight distribution than polymers made using metallocenecatalyst. The process used to produce the polymers is described in theart as the UNIPOL gas phase process. The catalyst used to produce thepolymers included a substituted phenylene aromatic diester internalelectron donor. The catalyst used is commercially available from W.R.Grace and Company and sold under the trade name CONSISTA. All copolymerswere made using triethylaluminum as a cocatalyst.

TABLE 1 Propylene-Ethylene Random Copolymer Examples Sample Ethylene wt.% XS (wt. %) wet XS/ET MFR (g/10 min) 1 4.44 6.61 1.49 87.0 2 4.48 5.411.21 44.5 3 3.80 5.03 1.32 42.4 4 4.30 5.85 1.36 42.1 5 3.78 5.00 1.3242.4 6 4.44 6.61 1.49 87.00 7 3.12 3.60 1.15 12.06 8 3.85 3.52 0.9114.03 9 3.89 3.52 0.90 11.79 10 3.80 5.03 1.32 42.36 11 4.30 5.85 1.3642.12 12 4.50 5.41 1.20 44.50 13 4.00 5.31 1.33 28.02 14 3.90 5.72 1.4726.00 15 4.20 6.14 1.46 16.31 16 3.50 4.41 1.26 12.59 17 3.50 4.41 1.2612.34 18 3.60 5.32 1.48 11.56 19 5.00 6.35 1.27 12.52 20 5.00 6.35 1.2711.71 21 2.5 2.98 1.19 22.99 22 2.52 3.48 1.38 25.14 23 2.53 3.01 1.1925.68 24 3.54 4.41 1.25 12.59 25 3.53 4.41 1.25 12.34 26 3.56 5.32 1.4911.56 27 5 6.35 1.27 12.52 28 4.98 6.35 1.28 11.71 29 2.55 3.33 1.3112.69 30 2.54 3.33 1.31 12.28 31 3.13 3.37 1.08 43.63 32 3.2 3.51 1.1043.6 33 3.15 4.42 1.40 45.2 34 2.79 3.98 1.43 52.98

Example No. 2

Another propylene-ethylene random copolymer was made in accordance withthe present disclosure using generally the same process as describedabove and compared to a control having all XS/ET ratio of 2. Thepropylene-ethylene random copolymers were injection molded into testplaques and tested for haze. Haze was tested initially and after thermalaging. The propylene-ethylene random copolymers are as follows:

TABLE 2 Propylene-Ethylene Random Copolymer Examples Sample Ethylene wt.% XS (wt. %) wet XS/ET MFR (g/10 min) Comparative 4.10 8.2 2.00 40.7 353.78 5.0 1.33 42.4

Haze was measured according to ASTM Test D1003, procedure A using thelatest version of the test. Haze was measured before and after 24 hourthermal aging at 55° C. using BYK Gardner Haze-Gard Plus 4725instrument. Thermal aging was conducted by placing the plaque samplesinto an oven. During thermal aging, propylene polymer compositions havea tendency to increase in haze. Haze is increased due to furthercrystallization within the polymer and/or due to the formation of a hazysurface layer, which is typically referred to as blooming.

In forming the test plaques, the propylene-ethylene random copolymerswere compounded with various stabilizers. In particular, the polymercompositions contained 500 ppm of a hindered phenolic antioxidant,namely pentaerythritoltetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). A phosphitestabilizer was added at an amount of 700 ppm. The phosphite stabilizerwas tris(2,4-ditert-butylphenyl)phosphite. An acid scavenger was addedat a concentration of 200 ppm. The acid scavenger used was ahydrotalcite. An antistatic agent was added at a concentration of 500ppm. The antistatic agent was composed of a distilled monoglyceride,particularly DIMODAN HS K-A GMS90 marketed by DuPont. A clarifying agentwas also added to the compositions at a concentration of 1800 ppm. Theclarifying agent used was1,2,3-tridesoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]nonitol,particularly Milliken Millad NX8000.

The polymer compositions were injection molded into plaques having threethicknesses at 40 mil, 80 mil, and 125 mil. The plaques were tested forhaze before and after oven aging. The following results were obtained:

Haze Measurement Before Oven % After Oven % After-Before % IncreaseVisual Smear Comparative  9.5 22.4 42.6 15.0 26.0 49.6 5.5 3.6 7.0 36.713.9 14.2 4 4 Sample 35 10.3 24.0 44.2 11.6 25.9 46.4 1.3 1.9 2.2 11.4 7.3  4.7 N N

As shown above, the propylene-ethylene random copolymer of the presentdisclosure had unexpectedly better haze properties in comparison tosimilar conventional propylene-ethylene random copolymers. For example,one significant result is the fact that there is no visual blooming orsmearing even after heat treatment.

As shown above, polymer compositions made in accordance with the presentdisclosure can display a haze at 40 mil of less than about 15%, such asless than about 12%, such as less than about 11%. In addition, afteraging for 24 hours at 55° C., the haze increase is less than about 15%,such as less than about 14%, such as less than about 13%, such as lessthan about 12%. When measuring an 80 mil sample, the initial haze isgenerally less than about 35%, such as less than about 30%, such as lessthan about 25%. After thermal aging for 24 hours at 55° C., the %increase in haze is generally less than about 12%, such as less thanabout 11%, such as less than about 10%, such as less than about 9%, suchas less than about 8%, such as less than about 7.5%. When measuring an125 mil sample, the initial haze is generally less than about 50%, suchas less than about 46%, such as less than about 45%. After thermal agingfor 24 hours at 55° C., the % increase in haze is generally less thanabout 10%, such as less than about 8%, such as less than about 6%, suchas less than about 5%.

Example No. 3

Propylene-ethylene random copolymer samples were produced using the sameprocedures as described in Example No. 1. The samples were tested forvarious physical properties. The following results were obtained:

Sample No. 36 37 38 XS(wt %) wet 3.5 7.9 9.4 MF (g/10 min) 11.8 12.111.4 Et (wt %) 3.9 4.1 4.2 Gardner Impact 10.0 26.4 71.3 Strength (at23° C. inch-lbs) Flex. Mod., (MPa) 164800 131800 128000 N-Izod,(ft-lb/in), RT 1.39 3.15 4.87 Haze, % 9.1 8.2 9.0

As shown above, Sample No. 36 had improved stiffness in relation toSample Nos. 37 and 38.

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. In addition, itshould be understood that aspects of the various embodiments may beinterchanged both in whole or in part. Furthermore, those of ordinaryskill in the art will appreciate that the foregoing description is byway of example only, and is not intended to limit the invention sofurther described in such appended claims.

What is claimed:
 1. A propylene-ethylene copolymer comprising: propyleneas a primary monomer; an ethylene content (ET) of from 2.0% to 5% byweight; a melt flow rate greater than 45 g/10 min and less than 100 g/10min; a xylene soluble fraction (XS) of from 2.0% to 7.0% by weight; anda xylene soluble fraction to ethylene content ratio (XS/ET) of less thanor equal to 1.51.
 2. The propylene-ethylene copolymer of claim 1,wherein the ethylene content is from 3.0% to 4.2% by weight.
 3. Thepropylene-ethylene copolymer of claim 1, wherein the ratio XS/ET is from0.90 to 1.50.
 4. The propylene-ethylene copolymer of claim 1, whereinthe ratio XS/ET is less than 1.30.
 5. The propylene-ethylene copolymerof claim 1, wherein the ratio XS/ET is less than 1.00.
 6. Thepropylene-ethylene copolymer of claim 1, wherein the xylene solublefraction (XS) and the ethylene content (ET) are below a line defined byequation XS=2.1e^(0.297(ET)).
 7. The propylene-ethylene copolymer ofclaim 1, wherein the xylene soluble fraction (XS) and the ethylenecontent (ET) are above a line defined by equation XS=1.4e^(0.297(ET)).8. The propylene-ethylene copolymer of claim 1, wherein thepropylene-ethylene copolymer is formed using a Ziegler-Natta catalystand a dicyclopentyldimethoxysilane (DCPDMS) based donor.
 9. Thepropylene-ethylene copolymer of claim 1, wherein the propylene-ethylenecopolymer is formed using a Ziegler-Natta catalyst and an-propyltrimethoxysilane (NPTMS) based donor.
 10. A polymer compositioncontaining the propylene-ethylene copolymer of in claim 1, wherein thepropylene-ethylene copolymer is present in the polymer composition in anamount greater than about 70% by weight.
 11. The polymer composition ofclaim 10, further comprising a clarifying agent.
 12. The polymercomposition of claim 11, wherein the clarifying agent comprises adibenzyl sorbitol.
 13. The polymer composition of claim 11, wherein theclarifying agent comprises a nonitol.
 14. The polymer composition ofclaim 11, wherein the polymer composition displays a haze at 40 mil ofless than about 15% and wherein after thermal aging for 24 hours at 55°C., the haze decreases by no more than about 15%.
 15. An injectionmolded article comprising the propylene-ethylene copolymer of claim 1.16. The propylene-ethylene copolymer of claim 1 having a molecularweight distribution (Mw/Mn) of greater than about 3.5.
 17. A hot fillpackaging container comprising the propylene-ethylene copolymer ofclaim
 1. 18. The hot fill packaging container of claim 17, wherein thehot fill packaging container has been formed through at least one ofinjection molding, blow molding, or thermoforming.